During the American Civil War, the
Union was a name used to refer to the federal government of the United States, which
was supported by the twenty free states and five border slave states. 11 Southern
states declared a secession to join together to form the Confederacy. Although the
Union states included the Western states of California, Oregon, and (after October
31,1864) Nevada, as well as states generally considered to be part of the Midwest,
the Union has been also often loosely referred to as "the North", both then and
now.